Liquid sterilizer



y 1942" R. E. BITNER 2,282,024

. LIQUID STERILIZER Filed Jan. 24, 1940 2 Sheets-Sheet l HG- 2 w 2 2 1,4 29

- 2 HIGH FREQUENCY GENERATOR INVENTOR R. s. -BITNER 2,282,02

LIQUID STERILIZER May 5, 1942.

Filed Jan. 24, 1940 2 Sheets-Sheet 2 FIG. 4

- HIGH FREQUENCY GENERATOR INVENTOR Patents ny 1942 UNlTED sr'rEs PATENT OFFICE I 2.25am j I LIQUID am I Ralph E. Bitner, New York, N. Y. Y Application January 24, 1940, Serial No. 315,342

4 Claims.

This application is a continuation in part of applicant's prior application, Serial-No. 122,305, I

filed January 25, 1937, now Patent No. 2,189,279.

The present invention relates to liquid sterilizers-which use a combination of ultra-violet light and high frequency electrical currents for their 'sterilizing'action, and it more particularly relates to convenient and efilcient structures for subjecting a liquid to both of the above sterilizing actions at the same time.

The principal object of. the present invention structure which may be inserted in a pipe line and perform its sterilizing action during the steady uninterrupted flow of the liquid.

that a tube base it may be positioned in the end portion and secured therein, forming a liquid tight seal.

The ultra-violet radiator tube It is similar to one of the radiator tubes shown and described in the above mentioned application, now Patent No. 2,189,279, and is characterized by the absence of lead-in wires, the provision of external .is to provide a structure by which liquids such as water, milk, or beer may conveniently be acted electrodes and high frequency electrical power supply. Usually the tubes are made of quartz because of the transparency to ultra-violet rays but glass tubes may be used instead, provided a sufficient amount of germ killing radiation can be obtained from them. -The radiator tube i5 is made with an annular jacket 16 surrounding the central light producing portion and at the upper end, a bulb i1 is provided to afiord a more secure means of support in the base i4.

Still another object is to provide a sterilizer 4 which is closed to the outside air and completes its sterilizing action without danger of oxidation.

Other objects and structural details of the invention will be apparent from the following description when read in connection with the accompanying drawings, wherein,

Fig. l is a sectional view of one form of the sterilizer showing the method of mounting the ultra-violet radiator. v

Fig. 2 is a cross sectional view taken along line 2-2 of Fig. 1. I i v Fig, 3 is a cross sectional view taken along line 3-4 of Fig. l. a

Fig. 4 is a sectional view of'a second form. of the sterilizer in which a different kind of ultraviolet radiator is used.

Fig. 5 is a partial elevational view showing intake pipe in section.

Fig. ,6 is a cross sectional view taken along lineHofFigJe' Referring now toFigs. 1, 2, and 3, a pipe cona high frequency field. At the upper end of the conduit 10 a 1' joint II is attached so thatthe.

liquid may be easily admitted to. the sterilizer. The top end portion of the conduit is formed An external electrode is formed around the bulb ll by first covering it with a metallic shell ii and then filling the intervening space between the two with molten lead to insure a tight conducting sheath. The radiator tube i5 is then placed in an insulator cup 20 as indicated in Fig. 1, and sealed in proper alignment by some melted insulating material 2! such as sulphur. This construction provides a liquid tight seal and a firm unyielding support for the radiator tube. The top portion of the shell I8 extends above the level of the insulating material 2i so that electrical contact may be made by means of-a spring clip 22.

The insulating cup 29 is firmly secured in the conduit by a tubular clamping member 23 which is threaded to fit the threaded portion l3. An

insulating disk 24 which may be made of Bakelite or hard rubber is secured to the clamp 23 in order to support the spring clip 22 and its binding post 25.

At the lower end of the radiator IS, a second bulb 28 is formed similar to the upper bulb but not so large. A conducting clamp 21 is placed around the bulb 26 to act as the second external electrode for the radiator tube and to this clamp a plurality of conducting vanes 28 are soldered (see Fig. 2). A similar clamp 29 is placed at the upper end of the vanes for mechanical purposes only and does not have to be made of conducting material.

Integral with the conduit and formed by die casting or other known methods is a plurality with a shoulder l2 and an internal thread I! so bounded by two fiat surfaces which provide a means for the eflicient transfer of high frequency currents.

A source of high frequency power is schematically indicated at ill with output leads connected to the binding post 25 and the conduit Ill. The

tions 30 and back to the generator. 3i.

As was explained in the above mentioned Patent 2,189,279, the designation high frequency is applied to a source of electric power when the frequency is at least one million cycles per second. At this frequency and with suiiicient voltage, the current will easily pass through the quartz walls of the upper and lower bulbs ll and 26, and through the liquid between the vanes 28 and partitions III. In accordance with common practice the radiator tube l5- is filled with approximately 8 millimeters pressure (Hg) of argon gas together with a few drops of mercury. The jacket I6 is fully exhausted to provide a-heat insulation means and an annular barrier which will separate the electric discharge from the liquid flowing in the condui 1 It will be obvious from the above details of construction that any liquid flowing through the conduit will be subjected to the action of ultraviolet light and high frequency currents simultaneously.

It is a well known fact that ultra-violet light has considerable germicidal action when used alone. Also the passage of high frequency currents through a liquid (often called diathermy action) has a distinct germ killing power. When used together, the simultaneous action produces a resulting sterilizing action which is greatly in excess of the sum of the actions taken separately.

While a considerable number of liquids designed to be used in this structure have a comparatively low resistance and will permit a current to flow through their volume by conductive action, it is also possible to use high frequency currents on liquids and gases having very high insulating properties. This is due to the capacity currents which will normally flow across a dielectric when bounded by two conducting plates. It has been found that the germ killing power of condenser currents is as effective as conductive currents.

Referring now to Figs. 4, 5, and 6, a conduit 40 is employed as the sterilizing chamber and is made of any suitable insulating material. Glass or fused quartz may be used but it has been found more convenient to utilize one of the transparent synthetic resins for this purpose. These are variously known under their trade names as Lucite, Polysterene, and. Crystalite and are desirable because of the ease with which they may be machined and worked with ordinary metal cutting tools.

The outer cylinder 4| is closed at both ends by washer-like pieces 42 and 43. An upper entrance pipe 44 is connected to the side wall 4| and is used to convey the liquid to be sterilized into the sterilizing chamber. A lower exit pipe 45 is attached to the conduit 4| in a similar manner and is used to convey the liquid away. Because of insulation difllculties, it has been found desirable to construct the pipes 44 and 45 of the same insulating material as the main conduit.

Concentrically aligned with the outer cylinder 4| is an inner tube 46 made of the same material as the other conduits and sealed at its ends to the washer-like pieces 42 and 43 thereby forming a closed toroidal chamber having a central portion 46 open at each end into which may be positioned a discharge tube 41 which when properly excited will become a radiator of ultra-violet light. This radiator may be similar to the one shown inFig. l but in Fig. 4 an alternate type is shown to illustrate the possibilities of this type of sterilizing unit. The envelope of this radiator must be transparent to ultra-violet rays and must be filled with a suitable substance capable of emitting ultra-violet light when properly energized. The type indicated in Fig. 4 is provided withintemal electrodes 48 and lead-in wires 49. By using this construction, low frequency electrical power (60 cycles per second) may be used to light the radiator 41 and thus make it independent of the high frequency field supply. Fig. 4 shows connecting wires 50 which deliver power from a secondary 5| of a constant current transformer 52 having a primary winding 53 connected directly to a standard 110 volt A. C. lighting supply. The constant current transformer 52 iswell known in the art and is used to supply neon tube signs and other similar discharge lamps.

Within the toroidal chambers formed by conduit 4|, inner tubing 45 and the end pieces 42 and 43, there are placed two helical conductors 54 and 55 alternately spaced. One of these conductors 54 is connected directly to the top end washer 42 and winds downward in the form of a convolute screw to the lower end washer 45.

The second conductor 55 is formed in the same manner as the first but is shorted by one full turn and is positioned as shown in Fig. 4 midway between the turns of the first conductor. With the two helical conductors in place there results two spiral spaces with common openings at the upper andlower pipes 44 and 45, each space bounded at its upper face by one conductor and at its lower face by the other conductor. If, now, a liquid is injected into these spiral spaces and electrical potential applied to the conductors, two electrical cells will result. l

At all points within the toroidal chamber, the surfaces of the conductors 54 and 55 are at an angle of from the axis of the radiator 41 and therefore present an unobstructed path for the ultra-violet rays to travel parallel to the conductor surface and irradiate the entire space between adjacent conductors.

A high frequency oscillator 56 is represented in Fig. 4, which may be any one of a number of well known devices for generating sustained high frequency electrical currents. Oscillator leads 5! convey the electrical power to the two helical conductors and 55 thereby energizing the elec-.

trical cell hereinbefore described and causing high frequency currents to flow through the liquid between the conductors.

It will be obvious'that the liquid in the structure shown in Figs. 4,5, and 6 will be acted upon simultaneously by ultra-violet radiation and high frequency currents in exactly the same manner as the liquid in the structure shown in Figs. 1, 2, and 3. The sterilizing action should be the same in either case. The two structures are shown to ofler a more flexible and diversified system which may be changed to suit the characteristics of the liquids to be sterilized.

When sterilizing liquids which have a-very low resistance it may become necessarylto rely on capacity'currents only and in such cases the conductive plates (51 and 55 in Fig. 4 and 28 and IE. in Fig. 1) may be encased or covered with a layer of-insulating varnish or resin.

While I have described what I consider to be a highly desirable embodiment ofmy invention, it is obvious that many changes in form could be made without departingfrom the spirit at my invention, and I therefore, do not limit myself to the exact forms herein'shown and described, nor to anything less than the whole of my invention as hereinbefore' set forth, and as hereinafter claimed.

I claim:

1. A sterilizer of the class described comprising in combination a conduit, an ultraviolet radiator, an electrical cell, and means for subjecting a liquid to the simultaneous action of ultra-violet rays and high frequency electrical power; said ultra-violet radiator comprising an elongated sealed envelope transparent to ultra-violet rays, a substance capable of emitting ultra-violet light within said envelope,-an electrode at each end of said envelope, and a source of electrical power for energizing said substance; said electrical cell comprising a plurality of conducting plates arranged in two groups, one group disposed about said envelope and connected to one of said electrodes, the othervgroup positioned in interspaced alternate arrangement with the plates of the first group and connected to the source of electrical power, and means for permitting the liquid toof conducting plates positioned around said envelope in parallel arrangement and connected to one of said electrodes, and a plurality of cooperating conducting surfaces arranged paraileltto said plates and secured to said conduit; said sterilizing means comprising a source of high frequency electrical power connected between said conduit and the other electrode.

3. A sterilizer comprising in combination, a-

conduit, an ultra-violet radiator within and sterilizing means for subjecting a liquid'to the simultaneous action of ultra-violet rays and high frequency power; said electric cell comprising a plurality of conducting plates positioned around said envelope in parallel arrangement, a plurality of cooperating conducting surfaces arranged parallel to said plates in interspaced relation and secured to said conduit, and a film of insulation covering the conducting plates and conducting surfaces; said sterilizing means comprising a supply of suitable electrical power for frequency electrical power; saidultra-violet radiator comprising an elongated sealed envelope transparent to ultra-violet rays, a. substance capabie of emitting ultra-violet light within said envelope, and an electrode at each end of said enenvelope and an electrode at each end of said envelope; saidelectric cell comprising a-plurality velope; said electric cell comprising a group of electrically connected conducting plates positioned around said envelope and a group of cooperating electrically connected surfaces arranged in interspaced relation to said plates; said sterilizing means comprising a supply of high frequency electrical power, the terminals of which are co nected to the conducting surfaces, and one of the electrodes, and an electrical connection between the conducting plates and the other electrode.

RALPH E.

said con-. (hit, an electrical cell also within said conduit, 

